Normalized alloy steels



United States Patent 3,1 10,635 Patented Nov. 12, 1963 Element-Continued: Percent by weight NonMALizno ALLOY STEELS f 9 Joh A, Gnlya, Lancaster, Pa, assignor to Lukens Ste l Molybdenum (HS-0'35 Company, Coatesville, Pa., a corporation of Pennsyl- Vanadlum Vania 5 Balance iron and incidental steel-making No Drawing. Filed July 24, 1961, Ser. No. 128,332 r id l 7 f 148-136) Preferred alloys are those restricted to the following. The present invention relates to improved Weldable normalized alloy steels characterized by excellent notch Element: Percent by Weight toughness throughout a wide range of thicknesses. The 10 C 013-021 present invention further relates to low-carbon low-alloy Mn 0595430 steels that are articularly useful in structural and pres- P Up to 0-035 sure vessel applications. Up to 0040 Steels used in structural and pressure vessel applica- K tion hould exhibit welda'bility, uniform high str ngth 15 N1 GAO-0'70 and notch toughness throughout a wide range of section Cr 0504190 thicknesses. In order to insure excellent weldability the MO 020-030 amount f carbon should be low and the tensile strength V 0503-0-08 and notch toughness of the steel increased with low Balaffcelron and mcldemalsteelmakm amounts of selected alloying elements. The problem of Tesldualsselecting the proper balance of alloying elements for a The above alloys including the preferred alloys can steel useful in structural and pressure vessel applications contain 002 to 9 0% aluminum and other deoxidizers i a difilclllt especially if Substantially uniform P P as well as conventional additives used in the preparation efties a range of Section thicknesses to be of fine-grained steels. Further, the alloys of the present obtained. This is evidenced in the available steels which invention can have 25 0 45% i h f Copper exhibit decreased Stmngth accompanied y a marked placing a like amount of iron when maximum resistance duction in notch toughness in the heavier sections. to atmospheric corrosion is i Efforts t0 compensate Strength 1055 y incl'fiasing The following examples are illustrative of the excellent Carbon content and quenching from austeni'iling teInPBPw properties of the alloys of the present invention. tures result in impairing the weldability, ductility and/or notch toughness characteristics of these steels. Further- Example I more, most alloy steels, Whether of the quenched or nor- Sections of approximately six inches of the following malized types, require a tempering or stress-relieving alloy were normalized at 1700 F., allowed to cool and treatment to develop adequate impact resistance, and tempered at 1100 F. Each heat treatment time was many structures or components are of such mass confour hours. The alloy analyzed asfiguration that such treatments are impractical after fabrication. Similarly, increasing the gage is unsatisfactory Percent by i for economic as well as dimensional reasons. Mn It is an object of the present invention to provide an P O 6 improved weldable normalized steel that is characterized 40 S (i014 by high strength and excellent notch toughness over a Si i 6 broad range of thicknesses. It is another object of the present invention to provide Cr 3, lowcarbon, low-alloy steel that is particularly useful M in structural and pressure vessel applications. V O u It is still another object of the present invention to pro- A1 8 vide an economical combination of alloying elements that Cu will have the above desirable characteristics. 5g -';""8 7 5?i 'f1;1;

These and other objects are achieved with alloys havin if n an 0 er mm enta stee m g residuals. mg the following compositions. Aft th f d h u 1 er e a orementione eat treatments, the longitu- Elemgtijon Percent g lgg g dinal mechanical properties at the quarter line of the plate tnickness were determined. Tensile data were ob- Manganese IO'9QTI'4O tained from Standard O.50 5-inch diameter specimens and Phosphorus P to impact data from standard Ch-arpy V-notch specimens, S l P to Results given in the following table show that adequate 51116011 (111-040 s rength and toughness is provided in heavy sections even Nickel 0.30-0.80 Without tempering:

Condition Yield, Tensile, ifi f 136K233? ai g f, at tih i p.s.i. p.s.i. Mimimurn percent ft.lbs. ft.lbs.

percent Samplel Normalized-.- 70.41; 109.911 21 59.8 59 17 SampleZ Norrlalized 79.4K 101. 7K 20 60.6 22

t e mpered.

Impact Inpact Yield, Tensile, E (2) RA. at 80 at 80 p.s.i. p.s.i. percent F., l\,

ft.-los. fit-lbs.

Sample 3 94.8K 116.211 22 50.5 61 25 Examples 11 and III Two additional sections of approximately six inches were normalized at 1700 F. for four hours, air cooled, and tempered at 1100" F. These sections were analyzed Wt. per- \Vt. percent, cen

Example Example 11 III E lenient 0. l5 1. 28 1. 07 C. 010 0. 008 0. 024 0. 025 0. 11 0. 14 0. 58 0. 03 0. 87 l. 00 0. 23 0. 27 0. 045 0. 048 0. l0 0. 02

NOTE.-Balance iron and incidental steel-malring residuals for both sections.

Tensile and impact data are recorded in the following table:

Yield Tensile Impact Strength Strength E(2) R.A. at -40 (1,000 (1,000 F., p.s.i.) psi.) ft.lbs.

Example II 89. 4 101. 7 60. 6 24 Example III 79.0 107. 5 21 53. 9 22 The above tests demonstrate that the low alloy steels of the present invention exhibit high strength accompanied by good notch toughness even at low temperatures. These desirable characteristics are present in the heavy sections of the alloy steels in the normalized condition with substantially equally favorable properties in the normalized and stress relieved condition.

The above description and drawings disclose several embodiments of the invention, and specific language has been employed in describing the several figures. It will, nevertheless, be understood that no limitations of the scope of the invention are thereby contemplated, and that various alterations and modifications may be made such as would occur to one skilled in the art to which the invention relates.

I claim:

1. An improved weldable normalized steel consisting essentially of Element: Percent by Weight Carbon 0.10-0.28 Manganese 0.90-1.40 Phosphorus Up to 0.04 Sulphur Up to 0.05 Silicon 0.11-0.40 Aluminum 0.02-0.10 Nickel 0.30-0.80 Chromium 0.50-1.00 Molybdenum 0215-03 5 Vanadium 0.02-0.10 Balance iron and incidental steel-making residuals,

a said steel being characterized in having high uniform strength and toughness through a wide range of thicknesses.

:2. An improved weldable normalized steel consisting essentially of Element: Percent by weight Carbon 0.13-0.21 Manganese 0.95-1.30 Phosphorus Up to 0.035 Sulphur Up to 0.040 Silicon 0.11-0.30 Aluminum a 002-0. 10 Nickel 0.40-0.70 Chromium 0.60-0.90 Molybdenum 0.20-0.30 Vanadium 0.03-0.08

Balance iron and incidental steel-making residuals,

said steel being characterized in having high uniform strength and toughness thnou-gh a wide range of thicknesses.

3. An improved weldable normalized steel consisting essentially of Element: Percent by weight Carbon 0.10-0.28 Manganese 0.90-1.40 Phosphorus Up to 0.04- Sulphur Up to 0.05 Silicon 0.11-0.40 Aluminum 0.02-0.10 Nickel 0.30-0.80 Chromium 0.50-1.00 Molybdenum 0.15-0.35 Vanadium 0.02-0.10 Copper 0.25-0.45 Balance iron and incidental steel-making impurities,

said steel being characterized in having high uniform strength and toughness through a Wide range of thicknesses.

4. An improved weldable normalized steel consisting essentially of Element: Percent by weight Copper 0.25-0.45 Carbon 0.10-0.28 Manganese 0.90-1.40 Phosphorus Up to 0.04 Sulphur Up to 0.05 Silicon 0.11-0.40 Aluminum 0.02-0.10 Nickel 0.30-0.80 Chromium 0.50-1.00 Molybdenum 0.15-0.35 Vanadium 0.02-0.10 Balance iron and incidental steel-making impurities,

said steel being charcterized in having high uniform strength and toughness through a wide range of thicknesses.

5. An improved weldable normalized low-alloy steel article consisting essentially of alloying elements of substantially 0.16 percent carbon, 1.24 percent manganese, 0.16 percent silicon, 0.60 percent nickel, 0.80 percent chromium, 0.27 percent molybdenum, 0.05 percent vanadium, 0.04 percent aluminum, 0.31 percent copper, and the remainder iron and impurities and elements in amounts which do not adversely affect the heat treatment characteristics of the steel, and characterized by a tensile strength in excess of 100,000 pounds per square inch through a wide range of thicknesses and high impact resistance in the range of i Fahrenheit.

6. An improved weld able normalized low-alloy steel article consisting essentially of alloying elements of substantially 0.15 percent carbon, 1.28 percent manganese, 0.11 percent silicon, 0.58 percent nickel, 0.87 percent chromium, 0.23 percent molybdenum, 0.045 percent vanadium, 0.10 percent aluminum, and the remainder iron and impurities and elements in amounts which do not adversely affect the heat treatment characteristics of the steel, and characterized by tensile strength in excess of 100,000 pounds per square inch through a Wide range of thicknesses and high impact resistance in a range of i 80 Fahrenheit.

7. An improved Weldable normalized lo w-alloy steel article consisting essentially of alloying elements of substantially 0.17 percent carbon, 1.07 percent manganese, 0.14 percent silicon, 0.63 percent nickel, 1.00 percent chromium, 0.27 percent molybdenum, 0.048 percent vanadium, 0.02 percent aluminum, and the remainder iron and impurities and elements in amounts Which do not adversely aifect the heat treatment characteristics of the steel, and characterized by a tensile strength in excess of 100,000 pounds per square inch through a Wide range of thicknesses and high impact resistance in a range of :thu Fahrenheit.

References Cited in the file of this patent UNITED STATES PATENTS 1,896,839 French Feb. 7, 1933 2,140,237 Leitner Dec. 13, 1938 2,565,953 Gaspari et al. Aug. 28, 1951 OTHER REFERENCES Case et 211.: Al in Iron and Steel, 1953, page 5 relied upon. Published by John Wiley & Sons, New York, NY. 

1. AN IMPOROVED WELDABLE NORMALIZED STEEL CONSITING ESSENTIALLY OF ELEMENT: PERCENT BY WEIGHT CARBON 0.10-0.28 MANGANESE 0.90-1.40 PHOSPHORUS UP TO 0.04 SULPHUR UP TO 0.05 SILICON 0.11-0.40 ALUMINUM 0.02-0.10 NICKEL 0.30-0.80 CHROMIUM 0.50-1.00 MOLYBDENUM 0.15-0.35 VANADIUM 0.02-0.10 BALANCE IRON AND INCIDENTAL STEEL-MAKING RESIDUALS, SAID STEEL BEING CHARACTERIZED IN HIGH UNIFORM STRENGTH AND TOUGHNESS A WIDE RANGE OF THICKNESSES. 